Bach 18 vs Curry 128D
The Curry 128D has a wider cup diameter, the Curry 128D features a deeper cup, the Bach 18 has a larger throat opening.
The internal diameter of the cup, measured at the widest point inside the rim.
Mouthpiece A
Bach 18
• Tuba
Cup diameter32.10 mm / 1.2638 in
Best suited for
High-volume projection — open throat for power
vs
Mouthpiece B
Curry 128D
• Tuba
Cup diameter32.51 mm / 1.2800 in
Best suited for
Orchestral playing — large cup for full, dark tone
High-volume projection — open throat for power
Cup Diameter
The Curry 128D has a cup diameter of 32.51 mm / 1.2800 in compared to 32.10 mm / 1.2638 in on the Bach 18 — a difference of 0.41 mm / 0.0162 in. A wider cup generally produces a fuller, darker tone but requires more air support.
Which is better?
Neither mouthpiece clearly dominates the other — the right choice depends on your embouchure, playing style, and the sound you're after. Try both if possible.